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Geochronology and magmatic character of the pliocene-pleistocene volcanism in Sardinia (Italy) |
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| Authors: | L Beccaluva M Deriu G Macciotta C Savelli G Venturelli |
| Institution: | 1. Institute of Petrography, University of Parma, Italy 2. CNR - Laboratory of Marine Geology, via Zamboni 67, Bologna, Italy 3. Institute of Mineralogy, University of Parma, Italy |
| Abstract: | The Pliocene-Pleistocene subaerial volcanic activity of the island of Sardinia developed from about five million years ago to the Pleistocene. Volcanism was mainly fissural, related to rifting of the Sardinian crustal block and connected to intraplate tensional tectonics involving at the same time the area of the Tyrrhenian Sea. Areally the most abundant rocks are basic, ranging in serial character from alkaline to subalkaline types. In some areas intermediate and salic lavas also occur; trachytic and phonolitic rocks are mainly associated with basalts of alkaline affinity, whereas rhyolites and dacites are mainly related to subalkalic basalts. K/Ar data show that lavas of different serial character (from alkalic to subalkalic) are produced on the island within the same time range, from about four to two million years; it is to be noted, however, that the early products (about 5 million years) are mildly alkalic in character whereas most of the youngest products (0.6–0.14 million years) are strongly alkalic. |
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